Severe storms to slice through 'hot, sticky' Northeast

June is anticipated to end on an active note in terms of severe weather in the Northeast, with millions of Americans at risk for dangerously potent thunderstorms into Wednesday night. Prior to the conclusion of the second heat wave of the season, severe thunderstorms from West Virginia to Maine can be fueled by sweltering heat.

"Some very strong thunderstorms have already flared up across the Northeast's interior during Wednesday afternoon," said AccuWeather Senior Meteorologist Carl Babinski.

Contrasting weather conditions will battle in the humidity-rich East, spurring powerful storms.

"A slow-moving cool front will be intersecting with some very hot, humid air, and it will trigger multiple lines of storms," said Babinski.

More than 15 million people are under a slight risk for severe weather while nearly 8 million are facing an enhanced risk as calculated by the Storm Prediction Center (SPC). Boston is among the cities currently in the enhanced area, which is the third-highest threat level the SPC issues.

This map shows the threat level for severe weather across the Northeast Wednesday, June 30, 2021 as designated by the NWS Storm Prediction Center.

Flash flooding and damaging winds will be two of the biggest risks these storms pose.

"Storms will continue to thrive in a very hot, sticky environment well into Wednesday evening as they approach major metropolitan areas like Boston, New York and Philadelphia," said Babinski.

The thunderstorms are also expected to target cities such as Portland, Maine; Pittsburgh, Pennsylvania; and Syracuse, New York.

"We could see severe weather anywhere from the eastern Great Lakes to the East Coast," said AccuWeather On-Air Meteorologist Kevin Coskren.

Even outside of the area AccuWeather meteorologists are emphasizing for concentrated severe weather risks, thunderstorms in parts of the Ohio Valley, Mississippi Valley and even a portion of the Plains states could turn heavy and gusty locally into Wednesday evening.

The biggest threats with these storms will include torrential downpours, as well as straight-line winds that could gust in excess of 60 mph, with an AccuWeather Local StormMax™ of 70 mph, according to Babinski. As a result, there could be downed trees and power outages, as well as street and highway flooding.

Straight-line winds are non-tornadic but powerful thunderstorm winds that can push trees and other objects in their way down in a single direction or in a fanlike pattern over a large distance.

Hail is not out of the question either, according to AccuWeather Senior Meteorologist Joe Lundberg.

The National Weather Service (NWS) had issued multiple severe thunderstorm watches (yellow) as of mid-afternoon Wednesday. (NWS advisories/AccuWeather map)

AccuWeather forecasters urge residents to ensure they have a way to receive severe weather warnings.

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Heavy, gusty and locally severe thunderstorms are forecast for part of the mid-Atlantic region Thursday. Storms will include the ongoing potential of flash flooding and strong wind gusts, as well as the risk of isolated tornadoes, especially in the Chesapeake Bay region.

Motorists should use caution on roadways as heavy rainfall can produce pooling of water and a heightened risk of hydroplaning at highway speeds. Some highly impacted roadways will include interstates 81, 90 and 95.

While dangerous, these storms can bring beneficial rain to parts of the Northeast in need of it. About 70% of the state of Maine is in moderate drought, according to the United States Drought Monitor. Bangor, Maine, for example, has received less than an inch of rain during June, which is 26% of the normal precipitation there.

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